کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7745622 | 1498258 | 2016 | 7 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Rate-determining elementary step of oxygen reduction reaction at (La,Sr)CoO3-based cathode surface
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
الکتروشیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
In order to give insight into the guiding principle of further improvement in surface reactivity of mixed-conducting cathode materials of solid oxide fuel cells, electrochemical impedance spectroscopy study was carried out on various LaCoO3- and (La,Sr)CoO3-based dense thin film electrodes with emphasis on the effect of oxygen partial pressure, Po2. The area specific conductivity corresponding to the surface reactivity, which is evaluated from the major impedance component appearing at low frequency range, shows a Po2-exponent of 1/2 irrespective of electrode material. After examining a series of possible elementary reaction steps in the oxygen reduction reaction, the universally observed Po2 dependence can be explained only by assuming that the rate-determining step is the reaction where surface bidentate peroxide ion reacts with an oxide ion vacancy in the cathode to yield two Oâ ions, one left at the surface and the other in the cathode interior. The origin of the minor impedance component often observed at higher frequency range is also discussed on the basis of its independence on Po2, which leads the authors to suggest that this impedance can be associated with the redox reaction between the surface Oâ and O2Â â in the cathode.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Solid State Ionics - Volume 285, February 2016, Pages 202-208
Journal: Solid State Ionics - Volume 285, February 2016, Pages 202-208
نویسندگان
Shogo Miyoshi, Ayano Takeshita, Satoshi Okada, Shu Yamaguchi,